The Ford Barn

jerdan · 03-23-2018, 12:08 PM

I have a stock 239 v/8 that idles rough. If I pull the cake out a little it smooths out. I have tried adjusting the mixture screws. It does't seem to make any difference. I can screw one all the way in and it still runs. If I turn the other one all the way in it will die. When I step on the throttle it hesitates. Any help is appreciated.

Mart · 03-23-2018, 12:55 PM

It sounds like the carb has some issues. Is it a Holley 94 type? It is probably running over rich due to one of many possible causes. Holleys running rich have been discussed on there many times.

Mart.

Anteek29 · 03-23-2018, 04:19 PM

I think my approach would be to rebuild the carb. Do you have a spare carb that you could throw on?

jerdan · 03-23-2018, 05:07 PM

Yes I do.

Anteek29 · 03-23-2018, 06:32 PM

Good...Let us know the outcome.

Ken/Alabama · 03-23-2018, 11:39 PM

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Carb issues. Plugged idle tube likely.

rotorwrench · 03-24-2018, 10:03 AM

They can get internal leaks from a bad or ill fitting power valve. If the idle screws are all the way in on either side, it's a good bet that the fuel is coming from somewhere else. Late type power valves don't always fit the old housings well but this can be remedied. Ford Barn member CharlieNY has a fix and is a good source of parts or for complete overhaul.

G.M. · 03-24-2018, 10:31 AM

Stick valves can cause ruff idle. Drizzle MMO down the carb while
engine is running and a pint in the gas tank. Drive about 25
miles and if that's the problem it should go away. G.M.

GB SISSON · 03-24-2018, 11:50 PM

Vacuum leak can cause rough idle too. Check your distributer connections and wiper hose and fittings. It is often that for me. To me a perfectly idling flathead V8 is a huge part of the draw. Nothing else idles like that when all is in order.

03-23-2018, 12:08 PM	#1
jerdan Member Join Date: Dec 2012 Posts: 60	Rough idle I have a stock 239 v/8 that idles rough. If I pull the cake out a little it smooths out. I have tried adjusting the mixture screws. It does't seem to make any difference. I can screw one all the way in and it still runs. If I turn the other one all the way in it will die. When I step on the throttle it hesitates. Any help is appreciated.

03-23-2018, 12:55 PM	#2
Mart Senior Member Join Date: May 2010 Location: Solihull, England. Posts: 8,744	Re: Rough idle It sounds like the carb has some issues. Is it a Holley 94 type? It is probably running over rich due to one of many possible causes. Holleys running rich have been discussed on there many times. Mart.

03-23-2018, 04:19 PM	#3
Anteek29 Senior Member Join Date: Dec 2014 Location: Santa Maria, CA Posts: 985	Re: Rough idle I think my approach would be to rebuild the carb. Do you have a spare carb that you could throw on? __________________ Alan 1929 Special Coupe 1941 Pick-Up 1955 Victoria

03-23-2018, 05:07 PM	#4
jerdan Member Join Date: Dec 2012 Posts: 60	Re: Rough idle Yes I do.

03-23-2018, 06:32 PM	#5
Anteek29 Senior Member Join Date: Dec 2014 Location: Santa Maria, CA Posts: 985	Re: Rough idle Good...Let us know the outcome. __________________ Alan 1929 Special Coupe 1941 Pick-Up 1955 Victoria

03-23-2018, 11:39 PM	#6
Ken/Alabama Senior Member Join Date: May 2010 Location: Alabama Posts: 3,257	Re: Rough idle Sponsored Links (Register now to hide all advertisements) Carb issues. Plugged idle tube likely.

03-24-2018, 10:03 AM	#7
rotorwrench Senior Member Join Date: Jun 2010 Location: San Antonio, Texas Posts: 16,422	Re: Rough idle They can get internal leaks from a bad or ill fitting power valve. If the idle screws are all the way in on either side, it's a good bet that the fuel is coming from somewhere else. Late type power valves don't always fit the old housings well but this can be remedied. Ford Barn member CharlieNY has a fix and is a good source of parts or for complete overhaul.

03-24-2018, 10:31 AM	#8
G.M. Senior Member Join Date: May 2010 Location: Florida and Penna. Posts: 4,471	Re: Rough idle Stick valves can cause ruff idle. Drizzle MMO down the carb while engine is running and a pint in the gas tank. Drive about 25 miles and if that's the problem it should go away. G.M. __________________ www.fordcollector.com

03-24-2018, 11:50 PM	#9
GB SISSON Senior Member Join Date: Jan 2014 Location: Orcas Island Washington Posts: 4,914	Re: Rough idle Vacuum leak can cause rough idle too. Check your distributer connections and wiper hose and fittings. It is often that for me. To me a perfectly idling flathead V8 is a huge part of the draw. Nothing else idles like that when all is in order. __________________ Owner/Operator of 'Jailbar Ranch' on the side of Mt. Pickett. Current stable consists of 1946 1/2 ton pickup turned woodie wagon with FH V8, 1947 Tonner Pickup (red) mostly stock with exception of a cummins 6at turbo diesel, 1946 Tonner Pickup (green) with 226 cu in 6 cyl flathead, 1979 Toyota landcruiser wagon, completely encased in 1947 Ford Jailbar sheet metal. Ok, cornbinder rear fenders..... 'Rusty ol' floorboards, hot on their feet' (Alan Jackson)